The invention relates to a system, device, and/or process for testing grounded neutral protection.
Currently, Underwriters Laboratory (UL) standard 943 requires a fault circuit to have a supervisory circuit. This supervisory circuit can require a test circuit that is used to test that the ground fault circuit interrupter (GFCI) is sensitive enough to detect small differential currents as low as approximately 6 ma. Furthermore, GFCIs are required to have grounded neutral protection. This means that if the output of the GFCI's neutral conductor is grounded the GFCI will detect and trip. A grounded neutral condition is a particularly dangerous condition because a grounded neutral condition provides a current path to ground as well as back through the neutral conductor, which in essence desensitizes the differential transformer from detecting a current imbalance that is potentially hazardous. An example of how a grounded neutral condition is created is when a ground line contacts a neutral line either before or after contacts. This condition is dangerous because the desensitizing of a normal current imbalance detector (differential transformer) may not accurately detect all the current that is present in a circuit. This can cause more current to pass through a person because some of the current is returned through the neutral conductor offsetting the true current passing through a person. Therefore, there is a need for a fault circuit interrupter having grounded neutral protection and a fault circuit interrupter configured to test this grounded neutral protection.